@misc{indiciae5967a70e96cf,
  title = {Estimated areas and volumes of sedimentary rock in the United States by province; statistical background data for U.S. Geological Survey Circular 860},
  author = {K. L. Varnes and G.L. Dolton},
  year = {1982},
  doi = {10.3133/ofr82666c},
  url = {https://pubs.usgs.gov/publication/ofr82666C},
  note = {Source identifier: ofr82666C}
}